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Maaliki D, Jaffa AA, Nasser S, Sahebkar A, Eid AH. Adrenoceptor Desensitization: Current Understanding of Mechanisms. Pharmacol Rev 2024; 76:358-387. [PMID: 38697858 DOI: 10.1124/pharmrev.123.000831] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 05/05/2024] Open
Abstract
G-protein coupled receptors (GPCRs) transduce a wide range of extracellular signals. They are key players in the majority of biologic functions including vision, olfaction, chemotaxis, and immunity. However, as essential as most of them are to body function and homeostasis, overactivation of GPCRs has been implicated in many pathologic diseases such as cancer, asthma, and heart failure (HF). Therefore, an important feature of G protein signaling systems is the ability to control GPCR responsiveness, and one key process to control overstimulation involves initiating receptor desensitization. A number of steps are appreciated in the desensitization process, including cell surface receptor phosphorylation, internalization, and downregulation. Rapid or short-term desensitization occurs within minutes and involves receptor phosphorylation via the action of intracellular protein kinases, the binding of β-arrestins, and the consequent uncoupling of GPCRs from their cognate heterotrimeric G proteins. On the other hand, long-term desensitization occurs over hours to days and involves receptor downregulation or a decrease in cell surface receptor protein level. Of the proteins involved in this biologic phenomenon, β-arrestins play a particularly significant role in both short- and long-term desensitization mechanisms. In addition, β-arrestins are involved in the phenomenon of biased agonism, where the biased ligand preferentially activates one of several downstream signaling pathways, leading to altered cellular responses. In this context, this review discusses the different patterns of desensitization of the α 1-, α 2- and the β adrenoceptors and highlights the role of β-arrestins in regulating physiologic responsiveness through desensitization and biased agonism. SIGNIFICANCE STATEMENT: A sophisticated network of proteins orchestrates the molecular regulation of GPCR activity. Adrenoceptors are GPCRs that play vast roles in many physiological processes. Without tightly controlled desensitization of these receptors, homeostatic imbalance may ensue, thus precipitating various diseases. Here, we critically appraise the mechanisms implicated in adrenoceptor desensitization. A better understanding of these mechanisms helps identify new druggable targets within the GPCR desensitization machinery and opens exciting therapeutic fronts in the treatment of several pathologies.
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Affiliation(s)
- Dina Maaliki
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, Lebanon (D.M.); School of Medicine, University of South Carolina, Columbia, South Carolina (A.A.J.); Keele University, Staffordshire, United Kingdom (S.N.); Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); and Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar (A.H.E.)
| | - Aneese A Jaffa
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, Lebanon (D.M.); School of Medicine, University of South Carolina, Columbia, South Carolina (A.A.J.); Keele University, Staffordshire, United Kingdom (S.N.); Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); and Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar (A.H.E.)
| | - Suzanne Nasser
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, Lebanon (D.M.); School of Medicine, University of South Carolina, Columbia, South Carolina (A.A.J.); Keele University, Staffordshire, United Kingdom (S.N.); Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); and Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar (A.H.E.)
| | - Amirhossein Sahebkar
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, Lebanon (D.M.); School of Medicine, University of South Carolina, Columbia, South Carolina (A.A.J.); Keele University, Staffordshire, United Kingdom (S.N.); Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); and Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar (A.H.E.)
| | - Ali H Eid
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, Lebanon (D.M.); School of Medicine, University of South Carolina, Columbia, South Carolina (A.A.J.); Keele University, Staffordshire, United Kingdom (S.N.); Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran (A.S.); and Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar (A.H.E.)
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Matarrese P, Maccari S, Gambardella L, Vona R, Barbagallo F, Vezzi V, Stati T, Grò MC, Giovannetti A, Catalano L, Molinari P, Marano G, Ambrosio C. Benzodiazepine diazepam regulates cell surface β1-adrenergic receptor density in human monocytes. Eur J Pharmacol 2023; 948:175700. [PMID: 37001579 DOI: 10.1016/j.ejphar.2023.175700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023]
Abstract
Downregulation of cell surface β-adrenergic receptors (β-AR) is an important adaptive response that prevents deleterious effects of receptor overstimulation. Various factors including reactive oxygen species cause β-AR downregulation. In this study, we evaluated the effects of ligands of the peripheral benzodiazepine receptor (PBR), a key protein in regulating oxidative stress, on surface density of endogenous β1-and β2-ARs in highly differentiated cells such as human monocytes, which express both β-AR subtypes. β-AR expression in human monocytes was evaluated by flow cytometry, qPCR and western blotting. Monocyte treatment with β-AR agonist isoproterenol did not change surface β1-AR density while downregulating surface β2-AR density. This effect was antagonized by the β-blocker propranolol. An opposite response was observed with benzodiazepine diazepam that led to a time-dependent reduction in β1-AR density. In particular, while no significant downregulation was observed after 3 h of treatment, only 63% of β1-ARs were still present on the cell surface after 48 h of treatment with diazepam at 1 μM. Treatment with the PBR antagonist PK11195, but not with propranolol, antagonized the effects of diazepam. No change in β1-AR-mRNA or protein levels was observed at any time after diazepam treatment. We also found that diazepam did not affect Gs-protein or β-arrestin-2 recruitment for both β-ARs in engineered fibroblasts, further suggesting that diazepam activity on β1-AR density is mediated by PBR. Finally, no sex-related differences were found. Collectively, these results indicate that monocyte β1-ARs are resistant to catecholamine-mediated downregulation and suggest that PBR plays an important role in regulating β1-AR density.
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Xing G, Woo AYH, Pan L, Lin B, Cheng MS. Recent Advances in β 2-Agonists for Treatment of Chronic Respiratory Diseases and Heart Failure. J Med Chem 2020; 63:15218-15242. [PMID: 33213146 DOI: 10.1021/acs.jmedchem.0c01195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
β2-Adrenoceptor (β2-AR) agonists are widely used as bronchodilators. The emerge of ultralong acting β2-agonists is an important breakthrough in pulmonary medicine. In this review, we will provide mechanistic insights into the application of β2-agonists in asthma, chronic obstructive pulmonary disease (COPD), and heart failure (HF). Recent studies in β-AR signal transduction have revealed opposing functions of the β1-AR and the β2-AR on cardiomyocyte survival. Thus, β2-agonists and β-blockers in combination may represent a novel strategy for HF management. Allosteric modulation and biased agonism at the β2-AR also provide a theoretical basis for developing drugs with novel mechanisms of action and pharmacological profiles. Overlap of COPD and HF presents a substantial clinical challenge but also a unique opportunity for evaluation of the cardiovascular safety of β2-agonists. Further basic and clinical research along these lines can help us develop better drugs and innovative strategies for the management of these difficult-to-treat diseases.
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Affiliation(s)
- Gang Xing
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.,Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Anthony Yiu-Ho Woo
- Department of Pharmacology, School of Life Sciences and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Li Pan
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.,Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Bin Lin
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.,Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Mao-Sheng Cheng
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.,Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
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Moore LE, Kapoor K, Byers BW, Brotto AR, Ghods-Esfahani D, Henry SL, St James RB, Stickland MK. Acute effects of salbutamol on systemic vascular function in people with asthma. Respir Med 2019; 155:133-140. [PMID: 31349187 DOI: 10.1016/j.rmed.2019.07.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Asthmatics are at increased cardiovascular disease risk, which has been linked to beta2(β2)-agonist use. Inhalation of β2-agonists increases sympathetic nerve activity (SNA) in healthy individuals, however the systemic impact of salbutamol in asthmatics using β2-agonists regularly is unknown. OBJECTIVES This study compared the systemic vascular responses to a clinical dose of salbutamol (Phase I) and following an acute increase in SNA (Phase II) in asthmatics and controls. METHODS Fourteen controls and 14 asthmatics were recruited for Phase I. On separate days, flow-mediated dilation (FMD) and peripheral arterial stiffness (pPWV) were evaluated at baseline and following either 400 μg inhaled salbutamol or a placebo inhaler. For Phase II, heart rate, blood pressure, vascular conductance, pPWV, and central (c)PWV were evaluated in response to a large increase in SNA brought on by cold-water hand immersion (i.e. cold-pressor test) or body-temperature water hand immersion (i.e. control) in 10 controls and 10 asthmatics. RESULTS Following salbutamol, asthmatics demonstrated reduced FMD (-3.0%, p < 0.05) and increased pPWV (+0.7 m/s, p < 0.05); however, salbutamol had no effect in controls. The cold-pressor test resulted in similar increases in blood pressure, vascular flow rates and conductance, pPWV, and cPWV in both asthmatics and controls, suggesting similar neurovascular transduction in asthmatics and controls. CONCLUSION Inhaled Salbutamol leads to increased arterial stiffness and reduced FMD in asthmatics. As asthmatics and controls had similar vascular responses to an increase in SNA, these findings suggest asthmatics have heightened sympathetic responses to β2-agonists which may contribute to the increased cardiovascular risk in asthma.
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Affiliation(s)
- Linn E Moore
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Karishma Kapoor
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Department of Psychology, Faculty of Science, University of Alberta, Edmonton, AB, Canada
| | - Bradley W Byers
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Andrew R Brotto
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Daniel Ghods-Esfahani
- Department of Biological Sciences, Faculty of Science, University of Alberta, Edmonton, AB, Canada
| | - Shelby L Henry
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada; Department of Rehabilitation Science, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Ryan B St James
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Michael K Stickland
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, AB, Canada.
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Shi Y, Shu ZJ, Wang H, Barnes JL, Yeh CK, Ghosh PM, Katz MS, Kamat A. Altered expression of hepatic β-adrenergic receptors in aging rats: implications for age-related metabolic dysfunction in liver. Am J Physiol Regul Integr Comp Physiol 2018; 314:R574-R583. [PMID: 29212811 PMCID: PMC6712558 DOI: 10.1152/ajpregu.00372.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Increased β-adrenergic receptor (β-AR)-mediated activation of adenylyl cyclase (AC) in rat liver during aging has been linked to age-related increases in hepatic glucose output and hepatosteatosis. In this study, we investigated the expression of β-ARs, individual receptor subtypes, and G protein-coupled receptor (GPCR) regulatory proteins in livers from aging rats. Radioligand-binding studies demonstrated that β-AR density increased by greater than threefold in hepatocyte membranes from senescent (24-mo-old) compared with young adult (7-mo-old) rats and that this phenomenon was blocked by food restriction, which is known to retard aging processes in rodents. Competition-binding studies revealed a mixed population of β1- and β2-AR subtypes in liver membranes over the adult life span, with a trend for greater β2-AR density with age. Expression of both β-AR subtype mRNAs in rat liver increased with age, whereas β2- but not β1-AR protein levels declined in livers of old animals. Immunoreactive β2- but not β1-ARs were preferentially distributed in pericentral hepatic regions. Levels of GRK2/3 and β-arrestin 2 proteins, which are involved in downregulation of agonist-activated GPCRs, including β-ARs, increased during aging. Insofar as sympathetic tone increases with age, our findings suggest that, despite enhanced agonist-mediated downregulation of hepatic β-ARs preferentially affecting the β2-AR subtype, increased generation of both receptor subtypes during aging augments the pool of plasma membrane-bound β-ARs coupled to AC in hepatocytes. This study thus identifies one or both β-AR subtypes as possible therapeutic targets involved in aberrant hepatic processes of glucose and lipid metabolism during aging.
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Affiliation(s)
- Yun Shi
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
- Department of Medicine, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Zhen-Ju Shu
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
- Department of Medicine, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Hanzhou Wang
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Jeffrey L Barnes
- Department of Medicine, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Chih-Ko Yeh
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio , San Antonio, Texas
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Paramita M Ghosh
- Departments of Urology and Biochemistry, University of California Davis , Sacramento, California
- Research Service, Veterans Affairs Northern California Health Care System, Mather, California
| | - Michael S Katz
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
- Department of Medicine, University of Texas Health Science Center at San Antonio , San Antonio, Texas
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Amrita Kamat
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
- Department of Medicine, University of Texas Health Science Center at San Antonio , San Antonio, Texas
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio , San Antonio, Texas
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Hinz L, Ahles A, Ruprecht B, Küster B, Engelhardt S. Two serines in the distal C-terminus of the human ß1-adrenoceptor determine ß-arrestin2 recruitment. PLoS One 2017; 12:e0176450. [PMID: 28472170 PMCID: PMC5417508 DOI: 10.1371/journal.pone.0176450] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 04/11/2017] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptors (GPCRs) undergo phosphorylation at several intracellular residues by G protein-coupled receptor kinases. The resulting phosphorylation pattern triggers arrestin recruitment and receptor desensitization. The exact sites of phosphorylation and their function remained largely unknown for the human β1-adrenoceptor (ADRB1), a key GPCR in adrenergic signal transduction and the target of widely used drugs such as β-blockers. The present study aimed to identify the intracellular phosphorylation sites in the ADRB1 and to delineate their function. The human ADRB1 was expressed in HEK293 cells and its phosphorylation pattern was determined by mass spectrometric analysis before and after stimulation with a receptor agonist. We identified a total of eight phosphorylation sites in the receptor's third intracellular loop and C-terminus. Analyzing the functional relevance of individual sites using phosphosite-deficient receptor mutants we found phosphorylation of the ADRB1 at Ser461/Ser462 in the distal part of the C-terminus to determine β-arrestin2 recruitment and receptor internalization. Our data reveal the phosphorylation pattern of the human ADRB1 and the site that mediates recruitment of β-arrestin2.
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Affiliation(s)
- Laura Hinz
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
| | - Andrea Ahles
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
- * E-mail: (AA); (SE)
| | - Benjamin Ruprecht
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
- Center for Protein Science Munich (CIPSM), Freising, Germany
| | - Bernhard Küster
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
- Center for Protein Science Munich (CIPSM), Freising, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Bavarian Biomolecular Mass Spectrometry Center, Technical University of Munich, Freising, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
- * E-mail: (AA); (SE)
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Edgell H, Moore LE, Chung C, Byers BW, Stickland MK. Short-term cardiovascular and autonomic effects of inhaled salbutamol. Respir Physiol Neurobiol 2016; 231:14-20. [PMID: 27236040 DOI: 10.1016/j.resp.2016.05.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/30/2016] [Accepted: 05/25/2016] [Indexed: 11/18/2022]
Abstract
Asthma independently increases the risk of developing cardiovascular disease. As inhaled β-agonists have systemic cardiovascular effects, and elevations in arterial stiffness and sympathetic nerve activity are associated with increased cardiovascular morbidity/mortality, this study examines the effect of salbutamol use on pulse wave velocity (PWV) and muscle sympathetic nervous activity (MSNA). Healthy men and women (26.2±1.5years) were recruited for: Day 1: 4 inhalations of placebo followed by 4 inhalations of salbutamol (4×100μg); Day 2: placebo only; Day 3: carotid-femoral PWV measurements before/after placebo/salbutamol. Heart rate (HR), mean arterial pressure (MAP), and carotid-radial PWV were obtained on Day 1 and 2. MSNA was obtained on Day 1. Salbutamol increased HR and total MSNA (Baseline1: 2.8±2.8au; Placebo: 2.4±2.1au; Baseline2: 2.7±3.0au; Salbutamol: 3.3±2.9au; p=0.05), with no changes in MAP or PWV. There were no effects of placebo on HR, MSNA, or PWV. Acute salbutamol use increases sympathetic activity suggesting that salbutamol could contribute to cardiovascular morbidity/mortality in individuals using inhaled β-agonists.
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Affiliation(s)
- Heather Edgell
- Department of Medicine, University of Alberta, Edmonton, T6G 2J3, Canada; School of Kinesiology and Health Sciences, York University, Toronto, M3J 1P3, Canada.
| | - Linn E Moore
- Department of Medicine, University of Alberta, Edmonton, T6G 2J3, Canada
| | - Carol Chung
- Department of Medicine, University of Alberta, Edmonton, T6G 2J3, Canada
| | - Bradley W Byers
- Department of Medicine, University of Alberta, Edmonton, T6G 2J3, Canada
| | - Michael K Stickland
- Department of Medicine, University of Alberta, Edmonton, T6G 2J3, Canada; G.F. MacDonald Centre for Lung Health, Covenant Health, Edmonton, T5K 0L4, Canada
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Ahles A, Rodewald F, Rochais F, Bünemann M, Engelhardt S. Interhelical interaction and receptor phosphorylation regulate the activation kinetics of different human β1-adrenoceptor variants. J Biol Chem 2014; 290:1760-9. [PMID: 25451930 DOI: 10.1074/jbc.m114.607333] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
G protein-coupled receptors represent the largest class of drug targets, but genetic variation within G protein-coupled receptors leads to variable drug responses and, thereby, compromises their therapeutic application. One of the most intensely studied examples is a hyperfunctional variant of the human β1-adrenoceptor that carries an arginine at position 389 in helix 8 (Arg-389-ADRB1). However, the mechanism underlying the higher efficacy of the Arg-389 variant remained unclear to date. Despite its hyperfunctionality, we found the Arg-389 variant of ADRB1 to be hyperphosphorylated upon continuous stimulation with norepinephrine compared with the Gly-389 variant. Using ADRB1 sensors to monitor activation kinetics by fluorescence resonance energy transfer, Arg-389-ADRB1 exerted faster activation speed and arrestin recruitment than the Gly-389 variant. Both activation speed and arrestin recruitment depended on phosphorylation of the receptor, as shown by knockdown of G protein-coupled receptor kinases and phosphorylation-deficient ADRB1 mutants. Structural modeling of the human β1-adrenoceptor suggested interaction of the side chain of Arg-389 with opposing amino acid residues in helix 1. Site-directed mutagenesis of Lys-85 and Thr-86 in helix 1 revealed that this interaction indeed determined ADRB1 activation kinetics. Taken together, these findings indicate that differences in interhelical interaction regulate the different activation speed and efficacy of ADRB1 variants.
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Affiliation(s)
- Andrea Ahles
- From the Institute of Pharmacology and Toxicology, Technische Universität München, 80802 Munich, Germany
| | - Fabian Rodewald
- From the Institute of Pharmacology and Toxicology, Technische Universität München, 80802 Munich, Germany
| | - Francesca Rochais
- the Rudolf Virchow Center for Experimental Biomedicine, Universität Würzburg, 97080 Würzburg, Germany
| | - Moritz Bünemann
- the Institute of Pharmacology and Clinical Pharmacy, Universität Marburg, 35043 Marburg, Germany, and
| | - Stefan Engelhardt
- From the Institute of Pharmacology and Toxicology, Technische Universität München, 80802 Munich, Germany, the German Center for Cardiovascular Research, Partner Site Munich Heart Alliance, 80802 Munich, Germany
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Laukova M, Tillinger A, Novakova M, Krizanova O, Kvetnansky R, Myslivecek J. Repeated immobilization stress increases expression of β3 -adrenoceptor in the left ventricle and atrium of the rat heart. Stress Health 2014; 30:301-9. [PMID: 23878066 DOI: 10.1002/smi.2515] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 05/24/2013] [Accepted: 06/21/2013] [Indexed: 11/12/2022]
Abstract
Stress is a contributor of many cardiovascular diseases. Positive inotropic and chronotropic effects of catecholamines are regulated via β-adrenergic receptors (ARs). Many reports exist concerning changes of cardiac β1 - and β2 -ARs in stress, but only a few deal with modulation of cardiac β3 -AR. Our aim was to analyze the expression and binding sites of β1 -, β2 - and β3 -ARs and adenylyl cyclase activity in the left ventricle, and β3 -AR expression and binding in the left atrium of rats exposed to acute and chronic immobilization stress (IMO). The concentration of noradrenaline in the ventricle decreased, while adrenaline increased, especially after repeated IMO. The mRNA and protein levels, and binding sites of β3 -subtype significantly rose following chronic IMO, while all parameters for β2 -AR dropped after single and repeated exposure. Similarly, the mRNA levels and binding sites for β3 -subtype increased in the left atrium as a consequence of chronic IMO. The rise in β3 -subtypes and a drop in β2 -subtypes resulted in inhibition of adenylyl cyclase activity within the left ventricle. Taken together, among other factors, up-regulation of β3 -AR could represent an adaptation mechanism, which might be related to altered physiological function of the left ventricle and atrium during prolonged emotional stress and might serve cardioprotective function during catecholamine overload.
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Affiliation(s)
- Marcela Laukova
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, USA; Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
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Bornholz B, Weidtkamp-Peters S, Schmitmeier S, Seidel CAM, Herda LR, Felix SB, Lemoine H, Hescheler J, Nguemo F, Schäfer C, Christensen MO, Mielke C, Boege F. Impact of human autoantibodies on β1-adrenergic receptor conformation, activity, and internalization. Cardiovasc Res 2012. [PMID: 23208588 PMCID: PMC3567785 DOI: 10.1093/cvr/cvs350] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aims Autoantibodies against second extracellular loops of β1-adrenergic receptors frequent in dilated cardiomyopathy confer myocardial dysfunction presumably via cAMP stimulation. Here, we investigate the autoantibody impact on receptor conformation and function. Methods and results IgG was prepared from patients with dilated cardiomyopathy, matched healthy donors (10 each) or commercial IgG preparations (2). IgG binding to β1-adrenergic receptor peptides was detected in 5 of 10 patients and 2 of 10 controls. IgG colocalization with the native receptor was detected in 8 of 10 patients and 1 of 10 controls (10 of 10 patients and 7 of 10 controls at >30 mg IgG/L). All IgGs exhibiting receptor colocalization triggered changes in receptor conformation (determined with fluorescent sensors) not stringently correlated to cAMP stimulation, suggesting the induction of more or less active receptor conformations. Receptor-activating IgG was detected in 8 of 10 patients but only 1 of 10 controls. In addition, IgG from 8 of 10 patients and 3 of 10 controls attenuated receptor internalization (measured by total internal reflection fluorescence microscopy). IgG-inducing inactive receptor conformations had no effect on subsequent cAMP stimulation by isoproterenol. IgG-inducing active receptor conformations dampened or augmented subsequent cAMP stimulation by isoproterenol, depending on whether receptor internalization was attenuated or not. Corresponding IgG effects on the basal beating rate and chronotropic isoproterenol response of embryonic human cardiomyocytes were observed. Conclusions (i) Autoantibodies trigger conformation changes in the β1-adrenergic receptor molecule. (ii) Some also attenuate receptor internalization. (iii) Combinations thereof increase the basal beating rate of cardiomyocytes and optionally entail dampening of their chronotropic catecholamine responses. (iv) The latter effects seem specific for patient autoantibodies, which also have higher levels.
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Affiliation(s)
- Beatrice Bornholz
- Institute of Clinical Chemistry and Laboratory Diagnostics, University Hospital, Moorenstrasse 5, Düsseldorf 40225, Germany
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11
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Hakalahti AE, Khan H, Vierimaa MM, Pekkala EH, Lackman JJ, Ulvila J, Kerkelä R, Petäjä-Repo UE. β-Adrenergic agonists mediate enhancement of β1-adrenergic receptor N-terminal cleavage and stabilization in vivo and in vitro. Mol Pharmacol 2012; 83:129-41. [PMID: 23066091 DOI: 10.1124/mol.112.080440] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The β(1)-adrenergic receptor (β(1)AR) is the predominant βAR in the heart and is the main target for β-adrenergic antagonists, widely used in the treatment of cardiovascular diseases. Previously, we have shown that the human (h) β(1)AR is cleaved in its N terminus by a metalloproteinase, both constitutively and in a receptor activation-dependent manner. In this study, we investigated the specific events involved in β(1)AR regulation, focusing on the effects of long-term treatment with β-adrenergic ligands on receptor processing in stably transfected human embryonic kidney 293(i) cells. The key findings were verified using the transiently transfected hβ(1)AR and the endogenously expressed receptor in neonatal rat cardiomyocytes. By using flow cytometry and Western blotting, we demonstrated that isoproterenol, S-propranolol, CGP-12177 [4-[3-[(1,1-dimethylethyl)amino]2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one], pindolol, and timolol, which displayed agonistic properties toward the β(1)AR in either the adenylyl cyclase or the mitogen-activated protein kinase signaling pathways, induced cleavage of the mature cell-surface receptor. In contrast, metoprolol, bisoprolol, and CGP-20712 [1-[2-((3-carbamoyl-4-hydroxy)phenoxy)ethylamino]-3-[4-(1-methyl-4-trifluoromethyl-2-imidazolyl)phenoxy]-2-propanol], which showed no agonistic activity, had only a marginal or no effect. Importantly, the agonists also stabilized intracellular receptor precursors, possibly via their pharmacological chaperone action, and they stabilized the receptor in vitro. The opposing effects on the two receptor forms thus led to an increase in the amount of cleaved receptor fragments at the plasma membrane. The results underscore the pluridimensionality of β-adrenergic ligands and extend this property from receptor activation and signaling to the regulation of β(1)AR levels. This phenomenon may contribute to the exceptional resistance of β(1)ARs to downregulation and tendency toward upregulation following long-term ligand treatments.
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Affiliation(s)
- Anna E Hakalahti
- Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland.
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12
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Cheng SB, Filardo EJ. Trans-Golgi Network (TGN) as a regulatory node for β1-adrenergic receptor (β1AR) down-modulation and recycling. J Biol Chem 2012; 287:14178-91. [PMID: 22378779 DOI: 10.1074/jbc.m111.323782] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Receptor down-modulation is the key mechanism by which G protein-coupled receptors (GPCRs) prevent excessive receptor signaling in response to agonist stimulation. Recently, the trans-Golgi network (TGN) has been implicated as a key checkpoint for receptor endocytosis and degradation. Here, we investigated the involvement of the TGN in down-modulation of β1-adrenergic receptor in response to persistent isoprotenerol stimulation. Immunofluorescent staining showed that ~50% of endocytosed β1AR colocalized with TGN-46 at 5 h. Disruption of the TGN by brefeldin A (BFA) led to the robust accumulation of endocytosed β1AR in Rab11(+) recycling endosomes, inhibited β1AR entry into LAMP1(+) lysosomes, and as a result enhanced β1AR recycling to the plasma membrane. The lysosomotropic agent, chloroquine, arrested the majority of endocytosed β1AR in the TGN by 4 h. Immunoblot analysis showed that either disruption of the TGN or blockage of the lysosome prevented β1AR degradation. Co-expression of GFP-arrestin-3 in β1AR cells increased the endocytosis of β1AR and facilitated its entry to the TGN but inhibited recycling to the plasma membrane. Arrestin-3-induced inhibition of β1AR recycling was reversed by BFA treatment, whereas chloroquine induced the accumulation of arrestin-3 with β1AR in the TGN. These results demonstrate for the first time that the TGN acts as a checkpoint for both the recycling and down-regulation of β1AR and that arrestin-3 not only mediates β1AR endocytosis but also its recycling through the TGN.
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Affiliation(s)
- Shi-Bin Cheng
- Division of Hematology and Oncology, Rhode Island Hospital and Brown University, Providence, Rhode Island 02903, USA
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13
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Jiang X, Pan H, Nabhan JF, Krishnan R, Koziol-White C, Panettieri RA, Lu Q. A novel EST-derived RNAi screen reveals a critical role for farnesyl diphosphate synthase in β2-adrenergic receptor internalization and down-regulation. FASEB J 2012; 26:1995-2007. [PMID: 22278941 DOI: 10.1096/fj.11-193870] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The β2-adrenergic receptor (β2AR) plays important physiological roles in the heart and lung and is the primary target of β-agonists, the mainstay asthma drugs. Activation of β2AR by β-agonists is attenuated by receptor down-regulation, which ensures transient stimulation of the receptor but reduces the efficacy of β-agonists. Here we report the identification, through a functional genome-wide RNA interference (RNAi) screen, of new genes critically involved in β2AR down-regulation. We developed a lentivirus-based RNAi library consisting of 26-nt short-hairpin RNAs (shRNAs). The library was generated enzymatically from a large collection of expressed sequence tag (EST) DNAs corresponding to ∼20,000 human genes and contains on average ∼6 highly potent shRNAs (>75% knockdown efficiency) for each gene. Using this novel shRNA library, together with a robust cell model for β2AR expression, we performed fluorescence-activated cell sorting and isolated cells that, as a consequence of shRNA-mediated gene inactivation, exhibited defective agonist-induced down-regulation. The screen discovered several previously unrecognized β2AR regulators, including farnesyl diphosphate synthase (FDPS). We showed that inactivation of FDPS by shRNA, small interfering RNA, or the highly specific pharmaceutical inhibitor alendronate inhibited β2AR down-regulation. Notably, in human airway smooth muscle cells, the physiological target of β-agonists, alendronate treatment functionally reversed agonist-induced endogenous β2AR loss as indicated by an increase in cAMP production. FDPS inactivation interfered with β2AR internalization into endosomes through disrupting the membrane localization of the Rab5 small GTPase. Furthermore, Rab5 overexpression reversed the deficient receptor down-regulation induced by alendronate, suggesting that FDPS regulates receptor down-regulation in a Rab5-dependent manner. Together, our findings reveal a FDPS-dependent mechanism in the internalization and down-regulation of β2AR, identify FDPS as a potential target for improving the therapeutic efficacy of β-agonists, and demonstrate the utility of the unique EST-derived shRNA library for functional genetics studies.
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Affiliation(s)
- Xiaofeng Jiang
- Program in Molecular and Integrative Physiological Sciences, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115, USA
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14
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Divergent agonist selectivity in activating β1- and β2-adrenoceptors for G-protein and arrestin coupling. Biochem J 2011; 438:191-202. [PMID: 21561432 DOI: 10.1042/bj20110374] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The functional selectivity of adrenergic ligands for activation of β1- and β2-AR (adrenoceptor) subtypes has been extensively studied in cAMP signalling. Much less is known about ligand selectivity for arrestin-mediated signalling pathways. In the present study we used resonance energy transfer methods to compare the ability of β1- and β2-ARs to form a complex with the G-protein β-subunit or β-arrestin-2 in response to a variety of agonists with various degrees of efficacy. The profiles of β1-/β2-AR selectivity of the ligands for the two receptor-transducer interactions were sharply different. For G-protein coupling, the majority of ligands were more effective in activating the β2-AR, whereas for arrestin coupling the relationship was reversed. These data indicate that the β1-AR interacts more efficiently than β2-AR with arrestin, but less efficiently than β2-AR with G-protein. A group of ligands exhibited β1-AR-selective efficacy in driving the coupling to arrestin. Dobutamine, a member of this group, had 70% of the adrenaline (epinephrine) effect on arrestin via β1-AR, but acted as a competitive antagonist of adrenaline via β2-AR. Thus the structure of such ligands appears to induce an arrestin-interacting form of the receptor only when bound to the β1-AR subtype.
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15
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Fuhs SR, Insel PA. Caveolin-3 undergoes SUMOylation by the SUMO E3 ligase PIASy: sumoylation affects G-protein-coupled receptor desensitization. J Biol Chem 2011; 286:14830-41. [PMID: 21362625 DOI: 10.1074/jbc.m110.214270] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caveolin (Cav) proteins in the plasma membrane have numerous binding partners, but the determinants of these interactions are poorly understood. We show here that Cav-3 has a small ubiquitin-like modifier (SUMO) consensus motif (ΨKX(D/E, where Ψ is a hydrophobic residue)) near the scaffolding domain and that Cav-3 is SUMOylated in a manner that is enhanced by the SUMO E3 ligase PIASy (protein inhibitor of activated STAT-y). Site-directed mutagenesis revealed that the consensus site lysine is the preferred SUMOylation site but that mutation of all lysines is required to abolish SUMOylation. Co-expression of a SUMOylation-deficient mutant of Cav-3 with β-adrenergic receptors (βARs) alters the expression level of β(2)ARs but not β(1)ARs following agonist stimulation, thus implicating Cav-3 SUMOylation in the mechanisms for β(2)AR but not β(1)AR desensitization. Expression of endothelial nitric-oxide synthase (NOS3) was not altered by the SUMOylation-deficient mutant. Thus, SUMOylation is a covalent modification of caveolins that influence the regulation of certain signaling partners.
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Affiliation(s)
- Stephen R Fuhs
- Department of Pharmacology, School of Medicine, University of California at San Diego, La Jolla, California 92093, USA
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16
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Hakalahti AE, Vierimaa MM, Lilja MK, Kumpula EP, Tuusa JT, Petäjä-Repo UE. Human beta1-adrenergic receptor is subject to constitutive and regulated N-terminal cleavage. J Biol Chem 2010; 285:28850-61. [PMID: 20587416 DOI: 10.1074/jbc.m110.149989] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The beta(1)-adrenergic receptor (beta(1)AR) is the predominant betaAR in the heart, mediating the catecholamine-stimulated increase in cardiac rate and force of contraction. Regulation of this important G protein-coupled receptor is nevertheless poorly understood. We describe here the biosynthetic profile of the human beta(1)AR and reveal novel features relevant to its regulation using an inducible heterologous expression system in HEK293(i) cells. Metabolic pulse-chase labeling and cell surface biotinylation assays showed that the synthesized receptors are efficiently and rapidly transported to the cell surface. The N terminus of the mature receptor is extensively modified by sialylated mucin-type O-glycosylation in addition to one N-glycan attached to Asn(15). Furthermore, the N terminus was found to be subject to limited proteolysis, resulting in two membrane-bound C-terminal fragments. N-terminal sequencing of the fragments identified two cleavage sites between Arg(31) and Leu(32) and Pro(52) and Leu(53), which were confirmed by cleavage site and truncation mutants. Metalloproteinase inhibitors were able to inhibit the cleavage, suggesting that it is mediated by a matrix metalloproteinase or a disintegrin and metalloproteinase (ADAM) family member. Most importantly, the N-terminal cleavage was found to occur not only in vitro but also in vivo. Receptor activation mediated by the betaAR agonist isoproterenol enhanced the cleavage in a concentration- and time-dependent manner, and it was also enhanced by direct stimulation of protein kinase C and adenylyl cyclase. Mutation of the Arg(31)-Leu(32) cleavage site stabilized the mature receptor. We hypothesize that the N-terminal cleavage represents a novel regulatory mechanism of cell surface beta(1)ARs.
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Affiliation(s)
- Anna E Hakalahti
- Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, FI-90014 Oulu, Finland
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17
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Ampatzis K, Dermon CR. Regional distribution and cellular localization of beta2-adrenoceptors in the adult zebrafish brain (Danio rerio). J Comp Neurol 2010; 518:1418-41. [PMID: 20187137 DOI: 10.1002/cne.22278] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The beta(2)-adrenergic receptors (ARs) are G-protein-coupled receptors that mediate the physiological responses to adrenaline and noradrenaline. The present study aimed to determine the regional distribution of beta(2)-ARs in the adult zebrafish (Danio rerio) brain by means of in vitro autoradiographic and immunohistochemical methods. The immunohistochemical localization of beta(2)-ARs, in agreement with the quantitative beta-adrenoceptor autoradiography, showed a wide distribution of beta(2)-ARs in the adult zebrafish brain. The cerebellum and the dorsal zone of periventricular hypothalamus exhibited the highest density of [(3)H]CGP-12177 binding sites and beta(2)-AR immunoreactivity. Neuronal cells strongly stained for beta(2)-ARs were found in the periventricular ventral telencephalic area, magnocellular and parvocellular superficial pretectal nuclei (PSm, PSp), occulomotor nucleus (NIII), locus coeruleus (LC), medial octavolateral nucleus (MON), magnocellular octaval nucleus (MaON) reticular formation (SRF, IMRF, IRF), and ganglionic cell layer of cerebellum. Interestingly, in most cases (NIII, LC, MON, MaON, SRF, IMRF, ganglionic cerebellar layer) beta(2)-ARs were colocalized with alpha(2A)-ARs in the same neuron, suggesting their interaction for mediating the physiological functions of nor/adrenaline. Moderate to low labeling of beta(2)-ARs was found in neurons in dorsal telencephalic area, optic tectum (TeO), torus semicircularis (TS), and periventricular gray zone of optic tectum (PGZ). In addition to neuronal, glial expression of beta(2)-ARs was found in astrocytic fibers located in the central gray and dorsal rhombencephalic midline, in close relation to the ventricle. The autoradiographic and immunohistochemical distribution pattern of beta(2)-ARs in the adult zebrafish brain further support the conserved profile of adrenergic/noradrenergic system through vertebrate brain evolution.
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18
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Spooren A, Rondou P, Debowska K, Lintermans B, Vermeulen L, Samyn B, Skieterska K, Debyser G, Devreese B, Vanhoenacker P, Wojda U, Haegeman G, Van Craenenbroeck K. Resistance of the dopamine D4 receptor to agonist-induced internalization and degradation. Cell Signal 2010; 22:600-9. [DOI: 10.1016/j.cellsig.2009.11.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 11/12/2009] [Accepted: 11/16/2009] [Indexed: 02/04/2023]
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19
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Jones BW, Hinkle PM. Subcellular trafficking of the TRH receptor: effect of phosphorylation. Mol Endocrinol 2009; 23:1466-78. [PMID: 19541745 DOI: 10.1210/me.2009-0119] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Activation of the G protein-coupled TRH receptor leads to its phosphorylation and internalization. These studies addressed the fundamental question of whether phosphorylation regulates receptor trafficking or endosomal localization regulates the phosphorylation state of the receptor. Trafficking of phosphorylated and dephosphorylated TRH receptors was characterized using phosphosite-specific antibody after labeling surface receptors with antibody to an extracellular epitope tag. Rab5 and phosphoreceptor did not colocalize at the plasma membrane immediately after TRH addition but overlapped extensively by 15 min. Dominant-negative Rab5-S34N inhibited receptor internalization. Later, phosphoreceptor was in endosomes containing Rab5 and Rab4. Dephosphorylated receptor colocalized with Rab4 but not with Rab5. Dominant-negative Rab4, -5, or -11 did not affect receptor phosphorylation or dephosphorylation, showing that phosphorylation determines localization in Rab4(+)/Rab5(-) vesicles and not vice versa. No receptor colocalized with Rab7; a small amount of phosphoreceptor colocalized with Rab11. To characterize recycling, surface receptors were tagged with antibody, or surface receptors containing an N-terminal biotin ligase acceptor sequence were labeled with biotin. Most recycling receptors did not return to the plasma membrane for more than 2 h after TRH was removed, whereas the total cell surface receptor density was largely restored in less than 1 h, indicating that recruited receptors contribute heavily to early repopulation of the plasma membrane.
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Affiliation(s)
- Brian W Jones
- Department of Pharmacology, University of Rochester Medical Center, Box 711, Rochester, New York 14642, USA
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20
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Tillinger A, Myslive��ek J, Nov��kov�� M, Krizanova O, Kvet��ansk�� R. Gene Expression of Adrenoceptors in the Hearts of Cold-Acclimated Rats Exposed to a Novel Stressor. Ann N Y Acad Sci 2008; 1148:393-9. [DOI: 10.1196/annals.1410.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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21
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Liang W, Hoang Q, Clark RB, Fishman PH. Accelerated dephosphorylation of the beta2-adrenergic receptor by mutation of the C-terminal lysines: effects on ubiquitination, intracellular trafficking, and degradation. Biochemistry 2008; 47:11750-62. [PMID: 18841999 DOI: 10.1021/bi800219q] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Agonist-mediated ubiquitination regulates some G protein-coupled receptors by targeting them to lysosomes for degradation. Phosphorylation also regulates receptor endocytosis and trafficking to lysosomes. To explore the roles of the two post-translational modifications, we mutated the three C-terminal lysines to arginines in the human beta 2-adrenergic receptor (beta 2AR) (K348/372/375R). The level of agonist-mediated ubiquitination of the mutant (3K/R) was greatly reduced compared to that of wild-type (WT) beta 2AR in whole cells and in cell-free assays. Downregulation of 3K/R also was attenuated compared to that of the WT, whereas internalization and recycling were more similar. During endocytosis, WT and 3K/R appeared in different vesicles and WT, but not 3K/R, was transported to lysosomes. Both were rapidly phosphorylated in agonist-stimulated cells, but upon agonist removal, the rate of dephosphorylation of 3K/R initially was approximately 5 times faster than that of WT. The increased rate also was observed in a cell-free, soluble assay and, thus, was not due to differences in receptor trafficking. Okadaic acid, a potent phosphatase inhibitor, reduced the level of dephosphorylation and increased the levels of lysosomal targeting and degradation of 3K/R. The reduced level of ubiquitination and rapid dephosphorylation of 3K/R appear to prevent it from being sorted to lysosomes in contrast to the phosphorylated and ubiquitinated WT beta 2AR. Our findings indicate that both phosphorylation and ubiquitination are involved in the intracellular sorting of beta 2AR between pathways of recycling to the plasma membrane and degradation in lysosomes, and that the rate of dephosphorylation may be another mechanism of regulating the sorting.
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Affiliation(s)
- Wei Liang
- Membrane Biochemistry Section, Laboratory of Molecular and Cellular Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
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22
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Krizanova O, Myslivecek J, Tillinger A, Jurkovicova D, Kubovcakova L. Adrenergic and calcium modulation of the heart in stress: from molecular biology to function. Stress 2007; 10:173-84. [PMID: 17514586 DOI: 10.1080/10253890701305754] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
There is strong evidence about the importance of catecholamines and calcium signaling in heart function. Also, interaction of these two systems is well documented. Catecholamines signal through adrenergic receptors, and further activate calcium transport either from the extracellular space, or from the intracellular calcium stores. This review summarizes current knowledge on catecholamine production in the heart, with special focus on the final enzyme in the catecholamine synthesizing pathway, phenylethanolamine N-methyltransferase (PNMT), in different cell types in the heart. Further, signaling through different types of adrenergic receptors in physiological conditions and after exposure to different stressors is discussed. Also, part of this review considers activation of an intracellular calcium transport system via inositol 1,4,5-trisphosphate receptor and to possible functional consequences in control and stress conditions.
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Affiliation(s)
- O Krizanova
- Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia.
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23
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Biolo A, Rosa AS, Mazzotti NG, Martins S, Belló-Klein A, Rohde LE, Clausell N. The role of adrenergic receptor polymorphisms in heart failure. Braz J Med Biol Res 2006; 39:1281-90. [PMID: 17053838 DOI: 10.1590/s0100-879x2006001000003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Accepted: 07/11/2006] [Indexed: 11/22/2022] Open
Abstract
The main function of the cardiac adrenergic system is to regulate cardiac work both in physiologic and pathologic states. A better understanding of this system has permitted the elucidation of its role in the development and progression of heart failure. Regardless of the initial insult, depressed cardiac output results in sympathetic activation. Adrenergic receptors provide a limiting step to this activation and their sustained recruitment in chronic heart failure has proven to be deleterious to the failing heart. This concept has been confirmed by examining the effect of beta-blockers on the progression of heart failure. Studies of adrenergic receptor polymorphisms have recently focused on their impact on the adrenergic system regarding its adaptive mechanisms, susceptibilities and pharmacological responses. In this article, we review the function of the adrenergic system and its maladaptive responses in heart failure. Next, we discuss major adrenergic receptor polymorphisms and their consequences for heart failure risk, progression and prognosis. Finally, we discuss possible therapeutic implications resulting from the understanding of polymorphisms and the identification of individual genetic characteristics.
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MESH Headings
- Cardiac Output, Low/genetics
- Cardiac Output, Low/physiopathology
- Disease Progression
- Humans
- Polymorphism, Genetic/genetics
- Prognosis
- Receptors, Adrenergic, alpha/genetics
- Receptors, Adrenergic, alpha/physiology
- Receptors, Adrenergic, beta/genetics
- Receptors, Adrenergic, beta/physiology
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Affiliation(s)
- A Biolo
- Grupo de Insuficiência Cardíaca e Transplante, Serviço de Cardiologia, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2350, 90035-003 Porto Alegre, RS, Brazil
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24
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Gurevich VV, Gurevich EV. The structural basis of arrestin-mediated regulation of G-protein-coupled receptors. Pharmacol Ther 2006; 110:465-502. [PMID: 16460808 PMCID: PMC2562282 DOI: 10.1016/j.pharmthera.2005.09.008] [Citation(s) in RCA: 361] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Accepted: 09/22/2005] [Indexed: 12/23/2022]
Abstract
The 4 mammalian arrestins serve as almost universal regulators of the largest known family of signaling proteins, G-protein-coupled receptors (GPCRs). Arrestins terminate receptor interactions with G proteins, redirect the signaling to a variety of alternative pathways, and orchestrate receptor internalization and subsequent intracellular trafficking. The elucidation of the structural basis and fine molecular mechanisms of the arrestin-receptor interaction paved the way to the targeted manipulation of this interaction from both sides to produce very stable or extremely transient complexes that helped to understand the regulation of many biologically important processes initiated by active GPCRs. The elucidation of the structural basis of arrestin interactions with numerous non-receptor-binding partners is long overdue. It will allow the construction of fully functional arrestins in which the ability to interact with individual partners is specifically disrupted or enhanced by targeted mutagenesis. These "custom-designed" arrestin mutants will be valuable tools in defining the role of various interactions in the intricate interplay of multiple signaling pathways in the living cell. The identification of arrestin-binding sites for various signaling molecules will also set the stage for designing molecular tools for therapeutic intervention that may prove useful in numerous disorders associated with congenital or acquired disregulation of GPCR signaling.
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Affiliation(s)
- Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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25
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Liang W, Fishman PH. Resistance of the human beta1-adrenergic receptor to agonist-induced ubiquitination: a mechanism for impaired receptor degradation. J Biol Chem 2004; 279:46882-9. [PMID: 15331590 DOI: 10.1074/jbc.m406501200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Down-regulation is a classic response of most G protein-coupled receptors to prolonged agonist stimulation. We recently showed that when expressed in baby hamster kidney cells, the human beta1-but not the beta2-adrenergic receptor (AR) is totally resistant to agonist-mediated down-regulation, whereas both have similar rates of basal degradation (Liang, W., Austin, S., Hoang, Q., and Fishman, P. H. (2003) J. Biol. Chem. 278, 39773-39781). To identify the underlying mechanism(s) for this resistance, we investigated the role of proteasomes, lysosomes, and ubiquitination in the degradation of beta1AR expressed in baby hamster kidney and human embryonic kidney 293 cells. Both lysosomal and proteasomal inhibitors reduced beta1AR degradation in agonist-stimulated cells but were less effective on basal degradation. To determine whether beta1AR trafficked to lysosomes we used confocal fluorescence microscopy. We observed some colocalization of beta1AR and lysosomal markers in agonist-treated cells but much less than that of beta2AR even in cells co-transfected with arrestin-2, which increases beta1AR internalization. Ubiquitination of beta2AR readily occurred in agonist-stimulated cells, whereas ubiquitination of beta1AR was not detectable even under conditions optimal for that of beta2AR. Moreover, in cells expressing betaAR chimeras in which the C termini have been switched, the chimeric beta1AR with beta2AR C-tail underwent ubiquitination and down-regulation, but the chimeric beta2AR with beta1AR C-tail did not. Our results demonstrate for the first time that beta1AR and beta2AR differ in the ability to be ubiquitinated. Because ubiquitin serves as a signal for sorting membrane receptors to lysosomes, the lack of agonist-mediated ubiquitination of beta1AR may prevent its extensive trafficking to lysosomes and, thus, account for its resistance to down-regulation.
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Affiliation(s)
- Wei Liang
- Membrane Biochemistry Section, Laboratory of Molecular and Cellular Neurobiology, NINDS, National Institutes of Health, Bethesda, Maryland 20892, USA
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26
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Debaigt C, Hirling H, Steiner P, Vincent JP, Mazella J. Crucial role of neuron-enriched endosomal protein of 21 kDa in sorting between degradation and recycling of internalized G-protein-coupled receptors. J Biol Chem 2004; 279:35687-91. [PMID: 15187090 DOI: 10.1074/jbc.m402751200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recycling of endocytosed G-protein-coupled receptors involves a series of molecular events through early and recycling endosomes. The purpose of this work was to study the role of neuron-enriched endosomal protein of 21 kDa (NEEP21) in the recycling process of neurotensin receptors-1 and -2. Here we showed that suppression of NEEP21 expression does not modify the internalization rate of both receptors but strongly inhibited the recycling of the neurotensin receptor-2. In contrast, overexpression of NEEP21 changes the behavior of the neurotensin receptor-1 from a non-recycling to a recycling state. Recycling of the neurotensin receptor-2 involves both the phosphatidylinositol 3-kinase and the recycling endosome pathways, whereas recycling of the neurotensin receptor-1 induced by overexpression of NEEP21 only occurs by the phosphatidylinositol 3-kinase-dependent pathway. Taken together, these results confirm the essential role of NEEP21 in the recycling mechanism and show that this protein acts at the level of early endosomes to promote sorting of receptors toward a recycling pathway.
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Affiliation(s)
- Colin Debaigt
- Institut de Pharmacologie Moléculaire et Cellulaire, Unité Mixte de Recherche 6097 du Centre National de la Recherche Scientifique, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
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